Climate variability increasingly threatens sustainable dairy production by compromising animal welfare, productivity, and resilience, particularly in tropical smallholder farming systems. This study evaluated the effects of climate variability on the physiological and behavioural welfare of dairy cattle across contrasting agro-ecological zones in Rwanda. A cross-sectional survey was conducted on 167 smallholder dairy farms in six districts representing the Central Plateau (Huye, Kamonyi, Nyanza, and Ruhango) and the Eastern Dry Zone (Nyagatare and Rwamagana). Ambient temperature and relative humidity were recorded during farm visits, while standardised animal-based measures assessed physiological indicators (body condition score, respiration rate, rectal temperature, lameness, and injuries) and behavioural responses (panting, shade seeking, prolonged standing, and reduced feed intake). Non-parametric statistical tests compared climatic variables and welfare indicators between agro-ecological zones. The Eastern Dry Zone recorded significantly higher ambient temperatures than the Central Plateau (26.56 ± 1.52°C vs. 21.82 ± 2.22°C; p < 0.001), whereas relative humidity was significantly higher in the Central Plateau (73.40 ± 18.30% vs. 66.16 ± 12.80%; p = 0.005). Cattle in the Eastern Dry Zone exhibited significantly higher respiration rates, rectal temperatures, panting scores, prolonged standing, reduced feed intake, heat stress scores, lameness, and injury prevalence (p < 0.05). Body condition score and shade-seeking behaviour did not differ significantly between zones. Ambient temperature correlated positively with respiration rate and rectal temperature, whereas relative humidity showed negative associations. These findings highlight the need for climate-smart housing, shade, water, nutrition, and routine welfare monitoring to strengthen resilience in Rwanda’s smallholder dairy systems.
Keywords: Agro-ecological zones, Climate Variability, animal-based welfare indicators, dairy cattle welfare, heat stress, smallholder dairy system
